Basic Leaf
Identification Key
to Common
West Virginia Trees
Compiled and illustrated by
John Northeimer,
West Virginia State Parks
Traveling Naturalist
This key uses leaf shape almost exclusively to assist
in the identification of the tree from which the leaf
originated. You will answer a series of questions
that gradually eliminate possibilities. Illustrations
are provided with most questions to help you select
the correct answer. You will eventually reach a tree
or group of trees that match your leaf shape
characteristics. You can then check your favorite tree
field guide to verify your selection (or select among
a group of listed possibilities).
The key starts by separating simple leaves
from compound leaves.
Simple leaves are leaves with a single leaf blade
per stem. The blade may be divided into rounded
or sharp-pointed lobes of varying shapes, but there
is still just one leaf blade per stem. Examples include
birches, dogwoods, elms, magnolias, maples, oaks,
and sassafras.
Compound leaves have more than one leaflet
per stem. They may be singly compound,
with leaflets arranged along a single leaf stem
(hickories, ashes, sumacs, locusts, and walnuts)
or doubly compound, with leaflets arranged along a
branched leaf stem (Hercules club and Kentucky
coffeetree). It is important to observe the entire
compound leaf. If you pick up the single detached
leaflet of a compound leaf, you could confuse it
with a simple leaf.
When a measurement is given it refers to the
leaf blade not including the leaf stem. Descriptive
terms are provided in parenthesis.
If you know which tree the leaf came from,
make a few notes on the color and texture
of the bark (smooth, scaly, rough, or furrowed).
Also look at the way the twigs are arranged
on the branch. If they branch in pairs, across from
each other, the branching is opposite. If they are
staggered along the branch (on one side and then
the other), the branching is alternate. Ashes,
buckeyes, and maples have opposite branching.
These additional characteristics may help you
in a final identification.
The links in this document are active, so anytime
you see blue type you can click to advance
to that section of the identification key.
Go to beginning of ID key.
Basic Leaf Identification Key
Is the leaf a simple leaf?
Go to A
–or–
Is the leaf a compound leaf?
Go to G
Is the leaf undivided?
Go to B
A
–or–
Does the leaf have clefts, lobes,
or other divisions?
Continue below.
___________________________________
Is the leaf star shaped?
Check Sweet Gum.
if not
Are some of the leaves glove
or mitten shaped?
Check Red Mulberry and Sassafras.
if not
Is the leaf tulip shaped?
Check Tulip Poplar.
if not
Go to C
Back to beginning of key.
Is the leaf oval, elliptical,
oblong, or linear in shape?
Go to D
B
–or–
Is the leaf heart-shaped (cordate)
or nearly heart-shaped?
Continue below.
___________________________________
Is the leaf stem (petiole) strongly
flattened? Check the Aspens.
if not
Does the edge (margin) of the leaf
have saw-like teeth (serrate)?
Check the Basswoods.
if not
Is the leaf large (7–14 inches long)
and fuzzy (pubescent) underneath?
Check Catalpa.
if not
Is the leaf under 7 inches in length?
Check Redbud.
Back to beginning of key.
Is the leaf about as wide
as it is long,
with three to five lobes?
Check the Maples
and Sycamore.
C
–or–
Is the leaf longer than it is wide,
with three or more lobes?
Check the Oaks.
(lobes can be rounded or
pointed on the ends)
Back to beginning of key.
Does the edge (margin)
of the leaf have saw-like
teeth (serrate)?
Go to E
D
–or–
Are the teeth rounded (crenate)?
Go to F
–or–
Is the edge (margin) smooth (entire)?
Continue below.
________________________________
Back to beginning of key.
Is the leaf large
(over 5 inches in length)
and either wider at the tip end
(obovate) or oval-shaped?
Check Pawpaw
and the Magnolias.
D
if not
Does the leaf smell sweet or spicy
(aromatic) when rubbed?
Check Spicebush.
if not
Do the veins of the leaf curve
or arch towards the edge
of the leaf (arcuate)?
Check the Dogwoods.
if not
Check Black Gum.
Back to beginning of key.
Are there teeth only
at the end of each leaf vein?
Check American Beech
and American Chestnut.
E
–or–
are there teeth at
and between the leaf veins?
Continue below.
________________________________
Is the leaf long and narrow (linear)?
Check the Willows.
if not
Does the edge (margin) of the leaf
have teeth on teeth (doubly serrate)?
Check the Elms, Birches,
American Hornbeam
and Hop-Hornbeam.
if not
Does the leaf have single teeth spaced
evenly along the edge?
Check the Cherries
and Serviceberries.
Back to beginning of key.
Is the leaf just a little longer
than it is wide?
Check Witch Hazel.
F
–or–
Is the leaf about twice
as long as it is wide?
Check Chestnut Oak.
Back to beginning of key.
Do the leaflets come
from the stem at the same point
in a hand shape (palmate)?
Check the Buckeyes.
G
–or–
Are there 3 to 5
coarsely toothed leaflets?
Check Box Elder.
–or–
Is the leaf doubly compound
(bipinnate)?
Check Hercules Club
and Kentucky Coffeetree.
–or–
Is the leaf
singly compound
(pinnate)?
Continue below.
__________________________________
Back to beginning of key.
Are the edges (margins)
of the leaflets smooth (entire)?
Check Black Locust.
G
–or–
Do the edges (margins)
of the leaflets
have a few or many
saw-like teeth
(serrate)?
Continue below.
________________________________
Are the last three leaflets larger
than the others, and do they originate
at the same point on the leaf stem?
Check the Hickories.
if not
Are most of the leaflets about the
same size and evenly distributed
on the stem?
Check the Ashes, Sumacs,
and Walnut.
Back to beginning of key.